Best isolation device for a tube pre-amp

On a concrete base going directly into the ground, inside a soundproof room! You asked....

Seriously, probably the best overall approach is one of the isolation platforms with the inflatable bladders, on a good rigid rack, plus damping rings on the tubes themselves.

I've heard great things about the symposium rollerblocks are the aurios mibs. I have the rollerblocks under my cd player...major improverment. DH cones and pads under preamp currently. They help alot...don't know if they qualify as best though...

They may not be current state-of-the-art, but the Townshend sinks are very good.

I got a very good improvement in mid-range clarity when I put a Townshend Seismic sink under my tube pre-amp. There was no downside to doing this, and the sink was much better than Vibrapods. The Seismic Sink is an air bladder type of platform like that mentioned by Karls above.

But interestingly, when I put the "sinks" under my Levinson transport and DAC, it badly screwed up PRaT. Cheers. Craig